Probably using a SCART adaptor, plugging the composite connections (yellow=video, red/white=audio) into the adaptor and then running a SCART lead to the TV. Presumably you're running out of inputs or something? If your TV has component inputs, I would buy the optional wii component cable (official) as the pic quality is much better, particularly on bigger screens.
Thanks Davepuma, I have a ~8 year old CRT Panasonic 28' which has both scart sockets taken with my Humax PVR and DVD player, only the Humax has 1 scart free which is possibly meant for audio kit. Am I right in rememberring that if I use a scart-splitter from my TV that the quality deteriates badly?
I would imagine that your Humax will simply pass the connection via the SCART input and output. You can get SCART switching units. If you go for one, seriously, don't waste your money on a cheap unbranded one. Joytech, JS-Technology all do good quality units and will pass RGB with no noticable drop in quality. I don't think you will need one though.